Snapping Hip: Dynamic Ultrasound of the Iliopsoas and Iliotibial Tract
Clinical Types of Snapping Hip
The internal (medial) variant is associated with the iliopsoas tendon at the level of the anterior surface of the hip joint. The external (lateral) variant is due to the movement of the iliotibial tract relative to the greater trochanter. Dynamic ultrasound allows verification of the source of the snap in real-time [source: Diagnostic Ultrasound: Musculoskeletal, Griffith, 2025].
Anatomical Landmarks and Approaches
According to the hip joint ultrasound protocol, the following are assessed:
| Approach | Structures Assessed |
|---|---|
| Anterior | Iliopsoas tendon, rectus femoris tendon, acetabular-labral junction, anterior joint compartment, anterior superior iliac spine; dynamic assessment of snapping iliopsoas tendon |
| Lateral | Tendons of the gluteus minimus and medius, tensor fasciae latae, iliotibial tract, gluteal muscles |
| Medial | Adductor tendons and muscles |
| Posterior / Deep Gluteal Space | Ischial tuberosity and origin of hamstring tendons, posterior thigh musculature |
The iliopsoas tendon is traced obliquely with an assessment of its proximity to the capsule over the femoral head and its attachment to the lesser trochanter of the proximal femur. The normal iliopsoas bursa between the tendon and joint is not visualized [Griffith, 2025].
Dynamic Examination Technique
For external snapping hip, the patient is positioned on their side (decubitus); flexion and extension of the examined limb help demonstrate impingement of the iliotibial tract on the greater trochanter [Griffith, 2025]. For the internal type, a dynamic assessment is performed on the anterior approach with provocative limb movements to identify abnormal 'snapping' displacement of the iliopsoas tendon.
What to Look For
Assess: presence/absence of iliopsoas bursa distension (bursitis), abnormal snapping movement of the iliopsoas tendon during dynamics, condition of the bursa in the region of the greater trochanter and tendons of the gluteus minimus/medius muscles, as well as abnormal snap during lateral dynamic assessment [Fundamentals of Musculoskeletal Ultrasound, Jacobson, 2026].
Example of a Normative Report
Sample protocol (right hip): limited assessment of the anterior labrum without features; no signs of iliopsoas bursa distension or snapping iliopsoas tendon on dynamic visualization; rectus femoris, sartorius, and proximal adductors are normal; lateral compartment without pathology, no abnormal bursa distension at the greater trochanter; tendons of the gluteus minimus and medius are normal; no abnormal snap detected on dynamic assessment. Conclusion: unremarkable [Jacobson, 2026].
Anisotropy Artifact
During tendon examination (including the iliopsoas), an anisotropy artifact may occur: when the beam is not parallel, the structure falsely appears hypoechoic. To eliminate, tilt the transducer (heel-toe / angulation, ~5–15°), restoring perpendicular beam incidence; if the 'finding' disappears upon tilting, it is an artifact, not pathology [Verified Answers from Medtrain Consortium, 2026].
Frequently asked questions
What is the patient position for assessing external snapping hip?
Side position (decubitus). Flexion and extension of the examined limb help demonstrate impingement of the iliotibial tract on the greater trochanter [Griffith, 2025].
How to visualize the iliopsoas tendon?
Obliquely: trace its close relation to the capsule over the femoral head and attachment to the lesser trochanter. The normal iliopsoas bursa between the tendon and joint is not visible [Griffith, 2025].
How to distinguish tendon anisotropy from pathology?
Tilt the transducer (heel-toe, ~5–15°) to restore perpendicular beam incidence. If the hypoechoic area disappears, it is an anisotropy artifact, not pathology [Medtrain, 2026].
What does dynamic assessment include when suspecting internal snapping type?
Dynamic visualization of the iliopsoas tendon on the anterior approach to identify abnormal snapping displacement, as well as assessment of iliopsoas bursa distension [Jacobson, 2026].